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The 1GR-FE is the 4.0L version. Bore is 94 mm and stroke is 95 mm. Output is 236 hp (183 kW) at 5200 rpm with 266 lb-ft (382 Nm) of torque at 4000 rpm on 87 octane, and 239 hp at 5200 rpm with 278 lb-ft at 3700 rpm on 91 octane. This engine features Toyota's single VVT-i, variable valve timing, system and a compression ratio of 10.0:1. Inside, the 1GR uses a taper-squish combustion chamber design with matching pistons to improve anti-knocking and engine performance, while also improving intake and fuel efficiency. Toyota adopted a siamese-type intake port, which reduces the surface area of the port walls and prevents fuel from adhering to such walls. This engine has special cast-iron cylinder liners cast into the block, which are a spiny type to improve adhesion between the liner and cylinder block. With these special thin liners it is impossible to bore the block. In the event of cylinder wall damage (scoring, deep protrusions, etc), the entire cylinder block must be replaced. For increased block rigidity, the 1GR also receives a high temperature plastic insulator/protector, which fills the empty space between the outer portion of the cylinders and block material common to open deck engines. For increased cooling efficiency, the 1GR employs water passages between the bores of the engine. There are such 2 passages for each bank for a total of 4. This reduces cylinder hot-spotting and keeps combustion chamber temperatures more uniform.
